Try this trick.
Take some instruments and put them up front.
Then take others and put them through the delay, with a very short delay, say 20ms.Do not let the dry signal through only the delayed signal to return to the board. Witht the slight delay it will be perceived that the 2nd set of instruments are back in the room. Put it all through a reveb now and increase a little on the distant instruments of the 2nd set.